Lever-jack.



PATENTBD MAY 14, 1907.

m A H J R B V u APPLIOATION FILED AUG. 7, 1905.

2 SHEETS-SHEET 1.

UNITED STATES PATENT OFFICE.

WILLIAM TREWI-IELLA, OF TRENTHAM, vidioRIA, AUSTRALIA, ASSIGNOR TO HIMSELF AND BENJAMIN TREWHELLA, or TRENTHAM, AUSTRALIA.

LEVER-JACK.

Specification of Letters Patent.

Patented May 14, 1907.

Application filed August '7, 1905. Serial No. 273,145.

To all wli/um, it may concern.-

Be it known that I, WILLIAM TREWHELLA, a subject of the King of Great Britain, residing at Trentham, in the State of Victoria, Commonwealth of Australia, have invented certain new and useful Improvements in Lever-Jacks, of which the following is a specification.

This invention relates to that kind of lever jack wherein the casing provided with a lift ing foot is adapted to climb up a rack or standard.

The improvements consist in providing a pair of horns on the-casing and a coinparatively long removable rod which rests on the foot of the casing and is raised and lowered with same. By the combined arrangement of the foot, horns and rod the jack is spe- .cially adapted for'operating on roots, stumps and trees in clearing land. The advantage ,of the rod is that it obtains a high grip on the object (such as a tree for instance) and thus greatly increases the leverage and lessens the labor. When the jack is employed for lifting stumps, logs and other comparatively low objects, the rod is removed and the horns are employed.

The invention is illustrated in the accornpanying drawings, in which Figure 1 is a side elevation of the lever jack with parts in section. Fig. 2, an enlarged front elevation (broken) of the rod. Fig. 3, a rear elevation of the jack. Fig. 4 is an enlarged detail plan view of the foot portion of the casing. Fig. 5, an enlarged horizontal section on line VV, Fig. 1, and Fig. 6 is an enlarged detail sectional view illustrating the mechanism for raising and lowering the casing.

A standard 1 of suitable height has a smooth face on one side and a rack 2 formed on the opposite side by means of which rack a casing 3 provided with a suitable pawl and ratchet mechanism, to be hereinafter described, is adapted to ascend and descend the standard. The casing surrounds the standard and has a foot 4 formed thereon near its base, said foot being provided with a socket 5, Fig. 4, in which the lower end of an extension rod 6, preferably of T-iron, is mounted. The rod is held in parallel relation to the standard by means of a guide 7, preferably detachably bolted to the upper end of the standard, said guide having hooks 8 which engage the flanges of the rod to permit it to slide through the guide.

The rib of the T-iron rod 6 extends below the flanges thereof and fits into the socket 5, while the ends of the flanges rest on the foot and support the weight. At the upper end, the flanges of the rod are tapered and bent over the rib and preferably formed with a sharpened bifurcated end 9 to enable it to obtain a good grip on the object to be raised.

Owing to the weight being on one side of the standard and the power mechanism in the casing on the other side, there is a tend ency to create friction between the casing and the standard. In order to minimize this friction the casing is so constructed that it is only in direct contact with the standard at its upper end, its lower end being provided with an anti-friction roller 10, adapted to ride against the smooth face of the standard.

In addition to the foot and extension rod, the casing is provided at its upper end with a pair of laterally projecting horns 11, 11, arranged on the sides of the casing and extend ing forwardly on each side of the rod and clear of the path of the. foot, the object of said horns being to enable the jack to lever objects of medium height, such as stumps of trees.

Thepawls and pawl-actuating mechanism which operate to raise and lower the casing 3 consist of, a rocker 12 mounted in bearings formed in the casing and is preferably further supported on a sectoral rocking lever 13,

whose convexface 14 bears on and rocks with the rocker 12, while its web 15 is stepped tion of the casing. Said rocking lever is imitedin its swing by pins 3, 3 on the wall of the casing.

The rocker 12 has two nearly circular recesses 17, 17, for the reception of the rounded foot ends of two pawls 18, 18, of different lengths. Said recesses are formed on opposite sides of the center of oscillation of the rocker and at such angles to said center as to impart to the pawls reciprocal movements, which in the case under consideration are equal to the space between two teeth of the rack 2, said rocker being provided with a lever 19 as one means of oscillating same.

To prevent longitudinal movement of the prawls and at the same time maintain their ee ends constantly in contact with the teeth of the rack, except when moved out of contact therewith for the purpose hereinafter described, said pawls are pivotally connected near the rocker, to one end of two connecting rods 20, 20, Whose opposite ends are pivotally connected to opposite ends of a balance lever 21 mounted in the free end of an arm 22, pivoted on a fixed pin 23, on one end of which is loosely mounted a disengaging lever 24. On the pin 23 is mounted a coiled spring 25, one end 26 of which exerts a ressure on the arm 22, by which the paw s are held against longitudinal movement, and also in contact with the rack 2 through the balance lever 21 and connecting rods 20, and yet per mit reciprocal motion of said pawls, each of which is provided with a pin or stud 18 adapted to be engaged by inclined faces of two lugs or projections 24, 24 on tl1e disengaging lever 24 above referred to, on which the other end 27 of spring 25 exerts pressure.

An eccentric or cam 28 is pivoted on one of the lateral walls of the casing 3 adapted to engage the disengaging lever 24 and move it laterally so that the lugs 24, 24 will be out of reach of the pins 18 on the pawls 18, when the movementof the casing is reversed.

The operation of the jack is as follows:

Assuming both pawls 18 in engagement with the rack 2, as shown in Fig. 6, and the rocker 12 rocked from right to left, the shorter pawl will lift the casing a distance equal to the space between two teeth, while the longerpawl will move up a corresponding distance and engage the tooth next above. By reversing the direction of oscillation of the rocker 12, the longer pawl will lift, and the shorter pawl will move up and engage the tooth next above, so that at each oscillating movement the casing will be raised a distance equal to the space between two teeth. The pawls are constantly held in contact with the teeth of the standard by the action of the spring 25 on the arm 22 and the action of the latter on the connecting rods 20 through the balance lever 21- which is free to follow the movement of the pawls. rection of motion of the casing it is necessary that the pawls 18 be alternately moved out of contact with the teeth of the standard. To this end the eccentric 28 is thrown back To reverse the diand the disengaging lever 24 is released so that it may swmg into operative position under the action of the spring 25.

I claim 1. A lever jack comprising a standard, a casing, means movable with the casing to raise and lower the latter on the standard, and an extension rod on the casing adapted to move parallel to the standard.

2. A lever jack comprising a standard, a casing, means to raise and lower the latter on the standard, a removable extension rod mounted on a foot on the casing, anda guide on the standard to guide the rod in parallel relation to the standard.

3. A lever jack comprising a standard, a casing, mechanism int e latter to raise and lower it on the standard, a foot formed on the casing havin a socket'therein, an extension rod removab fy mounted in the socket, and a guide mounted near the top of the standard through which the rod is adapted to slide.

4. A lever jack comprising a standard, a casing, means to raise and lower the latter on the standard, a foot on the casing, an extension rod removably mounted on the foot, a guide for said rod, and laterally projecting horns arranged on either side of the upper end of said casing and extending forward on each side of said rod.

5. A lever jack comprising a standard, a casing movably mounted thereon, an antifriction roller mounted in the casing adapted to roll on the standard, a foot on the base of the casing having a socket formed therein, an extension rod removably mounted in the socket, a guide for said rod mounted on the standard, and a pair of'lateral horns on the upper end of the casing,

6. A lever jack comprising a standard, a casin movably mounted thereon provided with orns at its upper end, and an anti-friction roller-'at its lower end.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

WILLIAM TREWHELLA.

Witnesses:

EDWARD NEEDHAM WATERS, ALFRED FORD. 

